SBIR-STTR Award

Photovoltaic cells used in Thermosphotovoltaic (TPV) applications should be tightly packed for maximum utilization of available photon illumination by the TPV emitter. In order to insure high reliability for emergency applications, protective diodes should be utilized. However, the diodes when mounted adjacent to the cells will take up valuable area and significantly decrease the efficiency of the TPV system. By embedding protective diodes within the substrate and utilizing multi-level conductors, the complete illumination area will be available for photovoltaic cells resulting in very array topography. Phase I will demonstrate feasibility of this approach. Phase II will develop a low cost, production-worthy design. 1) Develop candidate design/material combinations: 2) Perform Finite Element Analysis (FES) to select optimal combination; 3) Fabricate and test a feasibility test specimen; and, 4) Develop a protocol for cell selection and layout.

Commercial Applications and Other Benefits as described by the awardee:
Thermophotovoltaic systems need to have increased performance (efficiency) and higher reliability to be a viable commercial product. This project is intended to accomplish both of these goals. At the conclusion of Phase II, a high performance, high-reliability photovoltaic array will be available to the TPV systems industry to accelerate this important technology into mainstream use.

The use of photovoltaic (PV) cells for thermophotovoltaic (TPV) or reflective concentration systems will require a configuration that maximizes performance through dense cell packing and provides for high reliability through the use of bypass diodes. The lack of such a method is an impediment to the commercialization of TPV and reflective concentration systems. This project will use multi-layer substrates to imbed protective diodes underneath the PV cells so that precious module aperture area is not used. Additionally, PV cell reconfiguration will maximize the potential for dense packing. Phase I proved the viability of the dense cell packing concept as well as the concept of burying protective diodes into the dense cell array substrate. Computer analysis identified three potential substrate candidates. Phase II will take these three candidates to the prototype level. Performance, manufacturability, reliability, and cost analysis will be performed, and a successful substrate configuration will be chosen. All production processes, tooling, and equipment will be developed and implemented.

Commercial Applications and Other Benefits as described by the awardee:
The overall performance of TPV and reflective solar concentrator PV systems are highly dependent on the efficient utilization of the area being illuminated – the PV cell array. A cell array configuration for these applications that is optimized for performance and reliability, and that is combined with the technical advances in TPV emitter designs and recent reflective concentrator developments, should result in a cost-effective, efficient renewable energy source and the emergence of a vital new US industry.